Time
14 hours 13 minutes
Difficulty
Intermediate
CEU/CPE
20

Video Description

Lesson 4. Creating VM Snapshots This lesson discusses creating VM snapshots and covers the following:

  • Taking a snapshot
  • Managing multiple snapshots
  • Deleting snapshots
  • Consolidating snapshots

Snapshots are very useful in that they allow the preservation of the original state of the machine. You can see changes from before and after the snapshot was created. They're very useful if you're about the upgrade or patch a machine or make any configuration changes. If there are any complications, you can go back to the original snapshot and try again. Snapshots also allow the state of a disk and memory to be preserved.

Video Transcription

00:04
Hi, My name's Dean Pompilio. Welcome to Cyber Very. We're working with the virtual ization installation configuration Evangeline Course, and we're on module seven. Lesson four,
00:14
where we get to see how snapshots work.
00:18
So we'll see what's involved with taking a snapshot and how you manage
00:23
multiple snapshots.
00:25
What's involved with deleting a snapshot and doing the consolidation?
00:29
We'll see what that means.
00:31
Also, we'll talk about deleting of'em and then wrap up by doing lab number 12.
00:38
Okay, so snapshot is a very useful bit of functionality.
00:43
We, um
00:45
we can preserve the state of the virtual machine
00:47
on the lab as you'll see as we go through that, that you could make changes to the machine.
00:55
Uh, take a snapshot,
00:57
uh,
00:59
and then revert back and forth to see those changes before and after a snapshot was created
01:04
so I can return to a snapshot
01:07
as many times as I want.
01:10
There are some limitations
01:11
and some considerations for how you manage your snapshots as you
01:17
deal with them in a production environment.
01:19
But theoretically I can create as many snapshots as I want and be able to go back and forth among them to different points in time,
01:27
so this is very useful. For instance, if you are
01:30
about to upgrade a machine or about to patch it
01:34
or you're about to make some other configuration change,
01:37
which could be, ah, problematical destructive, you can always take a snapshot. First,
01:42
do your work. And then, if everything doesn't work out as expected, you could revert back to that snapshot
01:49
and try again.
01:52
So the setting ST
01:53
captures the dot Envy RAM file, the BMX file and the power state of the BM.
02:00
So snap shotting of'em that's power down. Obviously, that would be preserved.
02:05
We can also preserve the state of the disc
02:07
and optionally the memory.
02:10
Uh, preserving the member state might not always be needed, so it's something that you can keep us an option.
02:17
When you create a snapshot, you have several different files that are
02:22
created as well.
02:24
We have the VM name dot via Massa de that tracks all the snapshots of this being uses.
02:31
Then there's the Delta disc, and the Delta just tracks all the changes to the disk,
02:38
and it happened since the snapshot was created so that SVM name Dash Delta got B M D. K.
02:45
You have two very careful with the Delta disc files
02:47
if you create a snapshot
02:51
and you forget about it. For instance,
02:53
this dealt a disk file will continue to grow because it's continuing to track
02:58
all the changes to the disc. Since that snapshot was created
03:00
and there've been many times,
03:02
Ah, that I've seen
03:05
where someone creates snapshots, they forget about them, and all of a sudden your data stores filled up
03:09
and you have to go in and troubleshoot. You realize you've got adult of disk file
03:15
that might be many gigabytes and size,
03:16
so snapshots are not intended to be
03:21
something to keep Iran permanently. They're intended to be used when they're needed, and then you kind of clean up after yourself. Later,
03:29
the memory state is captured in Vienna, named asked
03:32
Dash Snapshot.
03:34
With a new miracle indicator,
03:37
This could rotate between zero through nine and then rotate again back around a zero. Depends how you got that configured, but you do have some options for how many of those files you can keep around.
03:47
Same thing with the snapshot description file and snapshot don't itself.
03:53
I've got a V M name
03:54
with some new miracle counter.
03:57
Uh, 000100002 and so on
04:01
with the dot vm kate
04:03
be indicate extension for the description file and then the dash delta for the V, M. D. K.
04:11
And these files Congrats. Just like the Delta disk file can grow. So you have to be careful with those. And don't forget they exist.
04:17
So you can probably imagine the storage within your data store
04:23
when you take a step, snapshot, weaken,
04:26
capture whether it's powered down or powered off or suspended. The VM can support snapshots and all three of those cases
04:32
remember, this is not a backup of your system,
04:35
even though it appears to function like a backup. It's on Lee capturing the changes between when the snapshot was made and what you've done since then.
04:44
So it's just those deltas that get captured, not the actual contents of the V M.
04:48
So make sure you have that that clear in your mind
04:53
when you make a snapshot, you want to give it a descriptive name.
04:56
You might even want to put a time stamp
04:58
in there so you can say, you know Saturday, December 25th
05:03
before patching or something of that nature. So now when I when I do other work, I wantto go back and revert back to that snapshot. I can see how this is the one that I created before I did my patching on this date.
05:15
And that way you can make your life easier by giving
05:18
snapshot e a name that's very descriptive.
05:23
We can also decide if you want a snapshot memory again. I said this was optional.
05:27
So there's a little check box and snapshot manager that allows you to decide that. And you can also have the option to qui es the guest file system.
05:36
So that means that the guest file system is quieted down to the point with a snapshot can capture as much information as possible
05:46
on the guest OS. This is another option, but you do need Veum were tools to use that particular option.
05:54
Snapshot Manager
05:56
gives you a display that looks somewhat like what we see here,
05:59
and this allows you to create your difference snapshots in a hierarchy
06:02
and so I can go forward and backward or go to snapshot, go back to another one and so on,
06:10
and you have the option to delete an individual snapshot or delete all the snapshots.
06:16
So regarding deleting and consolidation, Snapshot manager shows you what we see here.
06:23
I've got my base disc with some amount of data. Five gigabytes in this case.
06:29
And then I've got ah, snapshot 01
06:32
that's captured one gigabyte of Delta information. So that means that there's a gigabyte of data here
06:40
that's different from what my base disk contained.
06:43
So the base disc plus the snap Snapple one data is what's in this?
06:47
Um,
06:48
snapshot?
06:51
I might have another snapshot 02 Now, I've got two gigabytes of Delta information.
06:59
When you're looking at the snapshot manager, you get a little target symbol here saying you are here
07:04
that way. You know, if you revert to this snapshot, you are here, will be on this spot, could revert here, and it will move back and forth that way. When you're looking at this, you have some idea of where you are within the
07:17
snapshot hierarchy.
07:19
So some different since situations to keep
07:21
keep aware of here.
07:24
If you delete one of more levels above you are here. You can't return to that moment. So if I'm here and I still like this snapshot and delete it. I can no longer go back to that snapshot. That data is gone.
07:35
I basically am stuck with this snapshot
07:40
going forward until I take some other action.
07:43
If I delete my current snapshot,
07:46
for instance, I'm
07:46
currently here. If I delete this one
07:49
now, I revert back to whatever was the parent of that snapshot and I lose this data.
07:57
So keep that in mind where you are in the hierarchy. When you do, you're deleting.
08:03
If I delete a snapshot below, you are here.
08:07
So if this
08:07
this now moves
08:11
you are you are here is in this location
08:16
now, whatever was previously saved
08:18
in snap 02 is now gone.
08:20
I can't use it any longer. Then maybe something you want to do on purpose.
08:24
But just be careful
08:26
where you are when you do a deletion.
08:30
That's another good reason why you don't want to use a name like snap 02 or Snapple one. That doesn't mean anything, right?
08:35
Picking name that's descriptive before patching after patching before upgrade after upgrade things of that nature arm or helpful down the road.
08:43
I can also do a delete all operation within the snapshot manager.
08:48
This would basically
08:52
get rid of these two snapshots and consolidate that data into my base disc.
08:58
So it's it's Ah,
09:01
I'm sorry it doesn't consolidate the day I convinced the changes to the disk.
09:05
The consolidation is a different operation.
09:11
You might get a warning. If you have snapshots for IBM
09:15
within the within the century might get a little warning of the top level
09:18
received warnings. Things like things like
09:22
VM or tools needs to be upgraded or some other messages of this nature. You might see a message saying consolidation is required,
09:30
and that means that you've got some kind of break in the linkage between your snapshots and you need to consolidate. The VM are the snap snap shot Manager
09:41
might not even show that the snapshots exist,
09:43
but the files that we talked about earlier
09:46
these files might still exist in your data store. So you need to
09:52
go browse the data store, see that you've got files there
09:54
and that that would correlate to the to the message that you're getting saying that consolidation is needed
10:01
when you do the consolidation.
10:03
All of the changes
10:05
get rolled up back into the base of desk.
10:07
And this is a way to clean up after the fact that you've got snapshots that haven't been managed properly.
10:15
So just be careful when you're working with these so that you use them as needed and then make sure to do your clean up when you're done.
10:22
Okay, so as a recap,
10:24
one last thing. Sorry we didn't talk about deleting bm
10:26
You can right click of the M
10:30
and select removed from inventory
10:31
that just removes it from be centers inventory. It doesn't change
10:37
anything on the data store for the bm lives. However, you can right click of be Emma's well and below removed from the Victoria, there is a delete option
10:45
when you delete you really do get rid of all the files on the data store. So be careful with that option as well to make sure that you know that you actually want to remove the files that you're not gonna need them later.
10:56
All right, so, to recap, we talked about what snapshots actually do. What kinds of settings are captured when you do a snapshot.
11:05
We also look at the different file types and be aware that these Delta files will continue to grow as long as that snapshot exists.
11:13
So don't don't create snapshots and forget about them. Stay on top of that and manage it properly.
11:20
We know we can have the V empowered on Off are suspended.
11:24
We know that it's not a backup,
11:26
so keep those things in mind.
11:28
And when you're managing your snapshots using man snapshot manager,
11:33
be aware of where you are in the hierarchy before you do a delete, delete all or consolidation.
11:39
Okay, so next is
11:41
doing Lab 12
11:43
where you'll unregistered machine from the inventory. Just removing it from the inventory and you'll put it back into the inventory to see how that works.
11:52
You'll delete virtual machine from a disc,
11:56
then take snapshots of the virtual machine, revert back and forth to those snapshots
12:01
and then delete an individual snapshot. And then all of the snapshot.
12:07
All right, that concludes the lesson. Thank you

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Dean Pompilio
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